Tel Aviv — As more details emerge from leaked Palestinian documents on peace talks with Israel, attention is focusing on what some believe to be the source of the disclosure to Al Jazeera: a tiny agency staffed by young policy wonks who advise the Palestinian leadership on talks with Israel.

The Negotiations Support Unit, an 11-year-old foreign-funded agency overseen by Palestinian chief negotiator Saeb Erekat, has impressed local, foreign, and even top Israeli counterparts as a highly professional research organization. It keeps track of past Palestinian negotiating positions, develops new stances, conducts legal research, and engages in public relations.

On Monday evening, Israel's Channel 10 television news named a former NSU staffer as the source of documents describing Palestinian willingness to make concessions on Jerusalem, the borders of a future Palestinian state, and the rights of Palestinian refugees.

Former Israeli Foreign Minister Tzipi Livni, a top negotiator in the 2008 peace talks who figures prominently in the leaked documents, was reportedly so impressed with the NSU that she established a unit in the Foreign Ministry based on the NSU, Mr. Baskin says.

But he adds that the unit has been in turmoil after the departure of Maen Areikat, who oversaw the NSU until being appointed as chief representative of the PLO to the United States in 2009.

Palestinian negotiator: Documents 'genuine'

Palestinian negotiator Nabil Shaath declined to comment on the NSU, but said that the documents shown on Al Jazeera appear to be "genuine'' and reflect Palestinian negotiating positions – though he adds that they were taken out of context. "Probably they were stolen and sold,'' Dr. Shaath says.

The Palestinian government on Tuesday accused the Qatari news channel of "a campaign of incitement and deception'' to boost Hamas at the expense of the Western-backed Palestinian Authority (PA).

The PA said it has launched an investigation in to the leak, but an NSU official said that no one had been questioned yet.

Abbas: 'Something we're proud of'

A document released on Monday summarizing a March 2009 question-and-answer session with NSU staffers records Palestinian Authority President Mahmoud Abbas as saying that it would be "illogical'' for Israel to accept the return of millions of Palestinian refugees and descendants, contrary to the public demand of a right of return to homes in Israel.

Before the start of the session, Mr. Abbas was effusive in his praise.

"I always speak about the unit as something we are proud of,'' he says. "You are needed because without you the negotiations would be one-legged, and would not have a solid legal basis. Whenever we were at an important junction, we needed the NSU and you were there for us.''